1 / 40

What is the Elastic Rebound Theory ?

What is the Elastic Rebound Theory ?. Explains how energy is stored in rocks Rocks bend until the strength of the rock is exceeded Rupture occurs and the rocks quickly rebound to an undeformed shape Energy is released in waves that radiate outward from the fault.

elijah-logan
Download Presentation

What is the Elastic Rebound Theory ?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. What is the Elastic Rebound Theory? • Explains how energy is stored in rocks • Rocks bend until the strength of the rock is exceeded • Rupture occurs and the rocks quickly rebound to an undeformed shape • Energy is released in waves that radiate outward from the fault

  2. The Focus and Epicenter of an Earthquake • The point within Earth where faulting begins is the focus, or hypocenter • The point directly above the focus on the surface is the epicenter

  3. Where Do Earthquakes Occur and How Often? ~80% of all earthquakes occur in the circum-Pacific belt • most of these result from convergent margin activity • ~15% occur in the Mediterranean-Asiatic belt • remaining 5% occur in the interiors of plates and on spreading ridge centers • more than 150,000 quakes strong enough to be felt are recorded each year

  4. The Economics and Societal Impacts of EQs Damage in Oakland, CA, 1989 • Building collapse • Fire • Tsunami • Ground failure

  5. How is an Earthquake’s Epicenter Located? • Three seismograph stations are needed to locate the epicenter of an earthquake • A circle where the radius equals the distance to the epicenter is drawn • The intersection of the circles locates the epicenter

  6. epicenter focus Why do earthquakes occur? • Fractures, faults • Energy released and propagates in all directions as seismic wavescausing earthquakes

  7. Crater Lake, Oregon

  8. The Stump of Mount Mazama

  9. Ash What comes out of a volcano?

  10. Gas What comes out of a volcano? Most common: H2O CO2 SO2 HCl

  11. What comes out of a volcano? Lava

  12. Mauna Loa (Hawai’i): A typical shield volcano

  13. Mt. St. Helens: A typical composite volcano

  14. Mt. St. Helens after its 1980 eruption

  15. How Calderas Form

  16. Plate-tectonic setting of volcanism Explosive (andesitic) volcanoes form at subduction zones.

  17. Plate-tectonic setting of volcanism At spreading centers, low pressure triggers mantle melting—fluid basaltic magma rises.

  18. Plate-tectonic setting of volcanism Within plates, rising plumes of hotter mantle feed hot spots; varied volcanoes result (basaltic on Hawaii).

  19. Mt. St. HelensPyroclasticEruption

  20. Mount Saint Helens- after

  21. Mt. Saint Helens before

  22. Phreatic (vapor) eruption

  23. Bulge

  24. After the eruption

  25. Pyroclastic eruption

  26. Volcanic landscape: A Caldera (Crater Lake)

More Related